/*
 * Copyright (C) 2020 ActiveJ LLC.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.activej.inject;

import io.activej.inject.module.UniqueQualifierImpl;
import org.jetbrains.annotations.Nullable;

/**
 * This class holds utility methods used for validating and creating objects used as qualifiers.
 * Qualifiers serve as additional tags to distinguish different {@link Key keys} that have same type.
 * <p>
 */
public final class Qualifiers {

	public static Object uniqueQualifier() {
		return new UniqueQualifierImpl();
	}

	public static Object uniqueQualifier(@Nullable Object qualifier) {
		return qualifier instanceof UniqueQualifierImpl ? qualifier : new UniqueQualifierImpl(qualifier);
	}

	public static boolean isUnique(@Nullable Object qualifier) {
		return qualifier instanceof UniqueQualifierImpl;
	}

}
